Motor vehicles, such as motor cars and bikes, and motor lorries, are provided with an internal combustion engine. The engine has an exhaust system including a muffler.
Standard mufflers have a single path through the muffler casing. More advanced exhaust systems include one or more mufflers, with a number of differently sourced paths, with various exhaust paths being open and closed (or fixed with closed paths) depending on the operating speed of the engine, that is the exhaust flow rate.
Standard exhaust systems are known to provide a first exhaust path having a first flow resistance and therefore a back pressure, while performance after market exhaust systems have a second flow path in which the resistance is reduced (lower back pressure) to provide for improvement in performance.
A disadvantage of known exhaust systems having a muffler or muffler assembly providing a plurality of flow paths is that they are reasonably complex, and therefore costly, although providing greater sound reduction.